But that headline — and virtually all of the media coverage of the study — tells only a piece of the story: The findings confirm if a coal-fired plant is replaced with a gas-fired plant there is no net climate benefit for at least two decades.

Let’s briefly step back from this study to look the three essential reasons natural gas is not a “bridge” fuel to a carbon-free future. First, natural gas is mostly methane (CH4), a super-potent greenhouse gas, which traps 86 times as much heat as CO2 over a 20-year period.

Second, a great many studies have found that leakage rates are not small at all, especially as fracking has become more popular. “A review of more than 200 earlier studies confirms that U.S. emissions of methane are considerably higher than official estimates,” as one 2014 Stanford review research on methane leaks explained.

The study found methane emissions are so large, they “produce radiative forcing over a 20-year time horizon comparable to the CO2 from natural gas combustion.” That means the total warming from natural gas plants (leaks plus burning the gas) over a 20-year period is comparable to the total warming from coal plants over 20 year period.